Method of manufacturing lock nuts



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ATTORNEYS March 15, 1949. J. w. NEFF METHOD oF MANUFACTURING Loox NUTS1l Sheets-Sheet 3 Filed 0G13. 9, 1945 www Sw www.

INVENTOR QOH/v n//z/EFF 'BY ATTORNEYS March 15, 1949. J. w. NEFF2,464,412

METHOD 0F MANUFACTURING LOCK NUTS Filed 0ct.9, 1945 11 Sheets-Sheet 4INVENTOR ATTORNEYS ma@ i March 15, 1949.

Fildxxoot. 9, 1945 J. w. NEFF 2,464,41 2

METHOD 0F MANUFACTURING-'Loox NUTS 11 Sheets-Sheet 5 INVENTOR JO /V WEFF 447 t, BY A ATTORNEY:

Mal'Ch 15, 1949. J, W NEFF METHOD OF MANUFACTURING LOCK NUTS 11sheets-sheet e Filed Oct. 9, 1945 RF WN mw N .v www.

March 15, 1949. J. w. NEFF I 'METHOD 0F MANUFACTURING LOCK NUTS 11sheets-sheet 7 Filed Oct. 9, 1945` xNvEN-roR JOHN 14./ /VEFF 5 Y E N R OA J. W. NEFF METHOD 0F MANUFACTURING Loox NUTSy March 15, 1949.

` ll'Sheets-Sheet 8 Filed OG.. 9, .1945

INVENTOR BY 'bz I I ATTORN EYS Y /m JOHN W NEFF ll'sheets-sheet 9 INVENTOR JOHN 14./ /VEFF ATTQRNEYS lJ. W. NEFF METHOD OF MANUFACTURING LOCKNUTS March 15, 1949.

Filed OCT'. 9, 1945 March 15, 1949. J. w. NEFF l 2,464,412 l METHOD oFMANUFACTUMNG Loox NUTS Fued oct". 9, 1945 11 sheets-sheet 1o /6 6 /5/ 7INVENTOR Z /1 JOHN m /VEFF ATToRNEY March' 15, 1949. .l. w. NEFF2,464,412

METHOD OF MANUFACTURING LOCK NUTS Filed Oct. 9, 1945 11 She'ecs-Sheei'l11 Patented Mar. l5., 1949 METHOD F MANUFACTURING LOCK NUTS `lohn W.Neff, Easton, Pa., assignor to Stover Lock Nut da Machinery Corporation,a corporation of Delaware Application October 9, 1945, Serial No.621,273

(Cl. lil-86) 11 Claims.

l This invention relates to lock nuts and has for its object certainimprovements in the method of making lock nuts.

vNuts ordinarily are made with a pitch diameter sufficiently greaterthan the pitch diameter of a mating bolt so that the nut may be screwedfree ly onto the bolt. This so-called t tolerance may vary considerably,depending upon the size of the nut and the neness of fit desired. In anyevent, however, it is sufficient so that until the nut on the bolt comesinto engagement with the work to be held, the threads of the nut do notexert any substantial pressure on either the upper or the lower side ofthe bolt threads, and in consequence there is only slight friction andresistance to turning. When the nut becomes tightened against the work,the upper sides of the threads on the nut contact the lower sides of thethreads on the bolt with a pressure determined by the force with whichthe nut is tightened, and the friction resulting from the pressurebetween the interengaging sides of the threads serves to hold the nut inits tightened position. The objection to this kind -of nut is that it iseasily loosened, because whenever the pressure between the lower end ofthe nut and the work is relieved as a result of vibration, wear, orother cause, the pressure between the inter-engaging sides of thethreads is also relieved so that there is no longer sufcient friction toprevent the nut from being slowly backed off the bolt by vibration,shock, or the like.

Many different expedients have been proposed, and some have come intogeneral use, to prevent accidental loosening of tightened nuts. Thewellknown split lock-washer, the use of a separate lock nut and the useof cotter pins through cotter ways formed in the nut and through a holein the bolt, are probably the most familiar of these expedients. Anotherproposal is to insert elastic material in a groove specially providedaround the threaded hole of a nut to provide a locking effect. Theeffective use of such a nut is limited to the life of the elasticmaterial While continued in use with the Work to which it is firstapplied or the nut is greatly limited in the number of times it can bere-used because of damage to and loss of elasticity of the elasticmaterial. Other expedients have involved cutting specially shaped andfinely made threads on both nut and bolt, and the provision of speciallock sections formed integrally with or attached to the nut. Proposalsalso have been made to deform the nut as a whole, or to providespecially formed sections of the nut which may be deformed to lock withthe bolt. Such sections often are slotted in various ways with the ideaof enhancing the locking action of the deformed section. These variousprior expedients are subject to the disadvantage that aseparate lockingpiece is required, or to the disadvantage of being ineffective or onlymoderately effective, and difficult and expensive to manufactureaccurately and in quantity. For example, proposals to distort the nutover its entire length have been unsuccessful, because nuts so distortedto an effective degree cannot be started on the bolt except with greatdifficulty. Proposals to def-crm specially provided sections of the bolthave been unsuccessful because the deformed sections, which commonly areslotted in some manner, do not provide a satisfactory lock and areexpensive to manufacture.

Another lock nut proposed is one with opposite sides of a blank nutforced toward one another to provide an oval or elliptical opening atthe top while maintaining the lower part of the hole of the nutcylindrical or circular. Although such a lock nut was proposed manyyears ago in British Patent 1003 of 1880, so far as is known it has hadno commercial success. If the lock nut is deformed too little, it isWorthless. If it is deformed too much, it is not satisfactory becauseuse of the lock nut damages the threads of the nut as Well as of thebolt or mating screw, and the desired non-slipping gripping action isnot obtained. If the insufficiently deformed lock nut is givenadditional deformation, there is however no way of telling whether thedeformation is too much or too little7 except by actual use. Ac tual useis out of the question when the lock nuts are made by the thousands andshipped to remote parts for unfailing use.

Investigation confirms my discovery that lock nuts of the proper typeand amount of deformation may be consistently reproduced or duplicatedand that the deformation is sufficient to assure adequate gripping orlocking action between the lock nuts and their mating bolts or screws.

The lock nut preferably comprises a nut blank having a threaded opening,opposite sides of the main body of the blank being compressed at the topportion thereof to a depth of 1/4 to 1/2 the nominal diameter of themating screw beyond the elastic limit of the blank to provide apermanent distortion in the blank and to cause the top of the opening toassume a generally elliptical shape with the sides of the opening on theminor axis pushed toward one another and with the sides of the openingon the major axis pushed away from one another while the bottom of theopening remains substantially circular with a diameter greater than theminor axis and less than the major axis. The width of the top of theopening along the minor axis is reduced by the distortion by an amountequal to the t tolerance plus 0.001 to 0.010 inch.

In a presently preferred practice, the width of the top of the openingalong the minor axis is reduced by the distortion by an amounttopforduce a friction locking torque of 1151324" toi 3 820D2-5 on amating screw within the dimension tolerances of its class of t; in whichD equals the nominal diameter of the mating screw and the resultobtained is pound inches of torque.

In accordance with the invention, the method comprises the steps ofinserting a mandrel with a stop portion of predetermined size in thethreaded hole of a nut blank, forcing opposite sides of the nut towardone anotheruntil threads in the hole of the nut engage the stop portionof the mandrel to distort the upper portion of the nut a predeterminedamount, and knurling the top of the resulting lool: nut while stillmounted on its mandrel.

The depth of squeeze of the upper portion of the main body of the blankis highly important. A decrease in the depth of squeeze results in lesssensitivity (variation of friction torque in relation to change in boltdiameter) to bolt diameter and less life (re-use factor). An increase inthe depth of squeeze results in greater sensitivity to bolt diameter andgreater life. The object is to select a depth of squeeze adapted toyield the least sensitivity with the greatest life. If the depth ofsqueeze is less than 1li of the bolt diameter, the life of the lock nutis less than its practical limit. If the depth of squeeze is more thanl/g of the bolt diameter, the sensitivity of the lock nut is beyond thepractical limit. For these reasons, opposite sides of the main body ofthe blank are compressed only at the top portion thereof to a depth of1/2; to 1/2, preferably about 3/8, the nominal diameter of the matingscrew or bolt. This is particularly true of nuts ranging, for example,from #8 machine screw to 1I in size.

Lock nuts of the character described may be readily applied to a bolt ormating screw. They may be screwed on part way by hand since the lowerpart of the nut is substantially undistorted. At this point, theinwardly slanting opposite sides of the threaded opening in the nut comeinto contact with the bolt threads and as the nut is screwed on further,the bolt threads force the compressed sides of the nut apart against thespring action of the distorted nut.

These and other advantages of the invention will be better understood byreferring to the accompanying drawing, taken in conjunction with thefollowing description, in which- Fig. 1 is a side elevation of anapparatus illustrative of a practice of the invention, for the most partshowing its inner mechanism and not its outer casing or covering;

Fig. 2 is a partial plan view of the loading end of the mechanism;

Fig. 3 is a sectional elevational view of the apparatus showing theendless conveyor and part of the driving mechanism, the view being takenon a vertical plane along the line of movement of the nuts as shown inFig. 7

Fig. 4 is a partial plan view of the endless conveyor;

Fig. 5 is an exploded View of a unit of the endless conveyor showing asprocket chain link, a mandrel support and a mandrel with a nut mountedthereon;

Fig. 6 is a fragmentary side View of a small section of the endlessconveyor;

Fig. 7 is a sectional plan View on the line 7 1 of Fig. 1, showing theendless conveyor, the squeeze rolls, the driving mechanism for theendless conveyor, the adjusting mechanism for moving the endlessconveyor laterally and a portion of the driving mechanism for theknurling device;

Fig. 8 is a sectional view on the line 8 8 of Fig. 1, showing themounting of the squeeze rolls, the mechanism for driving the same and aportion of the adjusting mechanism for moving one of the squeeze rollslaterally;

Fig. 9 is a fragmentary sectional view on the line 9 9 of Fig. 8,showing the adjusting mechanism for moving the endless conveyor and itsassociated parts laterally, the squeeze rolls in phantom and part of theadjusting mechanism for moving one of the squeeze rolls laterally;

Fig. 10 is an enlarged sectional view of the mandrel support, showing agenerally cylindrical mandrel and a nut mounted thereon, before it isdeformed, similar to the assembly shown in Fig. 5;

Fig. 11 is asimilar sectional view showing the nut after it has beendeformed by the squeeze rolls;

Fig. 12 is a view similar to Fig. l1 but showing a generally taperedmandrel;

Fig. 13 is a plan view of a lock nut illustrative of the invention;

Fig. 14 is a side elevation;

Fig. 15 is a perspective view partly in section;

Fig. 16 is a side elevation partly in section, showing the lock nut anda bolt in applied form;

Fig. 17 is a view similar to Fig. 9, but showing the relative relationof the parts when deforming a smaller nut;

Fig. 18 is a section on the line l8--I8 of Fig. 17, showing the aligningmechanism for presenting a pair of opposite sides of the nut to thesqueeze rolls.

Fig. 19 is an exploded View showing the pedestals, the iiXed bearingblocks and the movable bearing blocks for the drive shafts of thesqueeze rolls and the appurtenant parts in the adjustment mechanism formoving one of the rolls laterally;

Fig. 20 is a general plan view of the endless conveyor support and itsrelated parts, the endless conveyor itself being omitted except for itschain sprockets;

Fig. 21 is a Side view, similar to Fig. 1, of the endless conveyorsupport and its related parts, the endless conveyor itself being omittedexcept for its chain sprockets, which are shown in phantom;

Fig. 22 is an enlarged elevation view of the knurling device shown inFigs. 1 and 3;

Fig. 23 is an end view of the same knurling device;

Fig. 24 is a section on the line 2li-24 of Fig. 22.;

Fig. 25 is a plan view confined to the tension control mechanism of theknurling device;

Fig. 26 is a sectional view on the line 26-26 of Fig. 23;

Fig. 27 is an enlarged elevational view of the adjusting mechanism formoving one of the squeeze rolls laterally, as shown in Figs. 1, 7, l8,9, 17 and 19, and showing more particularly the connecting mechanismwith an indicator for showing the amount of lateral movement of thesqueeze roll; and

Fig. 28 is a front View of the indicator `and its associated mechanism.

Referring first to Fig. 1, the nut deforming and knurling apparatuscomprises a pair of upright spaced pedestals 39 and 3l maintained inspaced relationship at their bottom by means of .a plurality of channels32, 33. The pedestals .in turn support a loading table 34, a casing orcover 35, most of which is shown broken away, an endless conveyor 36, apair of spaced vand opposed -squeeze rolls 31 and 38, a knurling device39, and

the necessary driving mechanism 40 for operating the apparatus. Thedriving mechanism comprises a motor 45 with a chain sprocket 46 mountedon a shaft 41. An endless sprocket chain 48 is mounted on the sprocketand a larger sprocket 49 mounted on a drive shaft 50. The drive shaft isemployed to drive the endless conveyor as well as the squeeze rolls.

Referring next to Figs. 8' and 19, sprocket 49 and drive shaft 50 aresupported in fixed bearings `I and 52 suitably mounted on brackets 53and 54 secured to pedestals 80 and 3|, respectively. A

bevel pinion 55 is suitably secured to an intermediate portion of driveshaft 50, the bevel pinion meshing with a beve1 gear 56 integrallymounted on the lower end of a vertical shaft 51. The shaft extendsupwardly through -a collar 58, a lower xed bearing block 59 providedwith a lower bearing hub 80, and an upper bearing hub 6|, squeeze roll88, upper xed bearing block 62 provided with a lower beaiing hub 63 andan upper bearing hub 64, and a spur gear 65 integrally secured to theupper end. An end plate 66 is bolted to the ends of lower xed bearingblock 59 and upper xed bearing block 62. Spur gear 65 meshes with acompanion spur gear integrally secured to the upper end of a verticalshaft 1|. This shaft eX- tends successively through an anti-frictionwasher 12, an upper laterally sliding bearing block 13, provided withfour (4) guide bars 13', as shown, extending through a complementaryslot 14 in upper fixed bearing block 62, squeeze roll 31, a lowerlaterally sliding bearing block 15, provided with guide bars as shown,extending through a complementary slot 16 in lower Xed bearing block 59.

The arrangement shown permits a variable space 30 between squeeze rolls31 and 38. The apparatus is so designed that the space may be varied toaccommodate nuts of various sizes. To this end, upper iXed bearing block62 is provided at its end with a lateral opening 8| accommodating a drawnut 82. The draw nut, as shown in Fig. 19, is provided with a generallyrectangular end or base portion 83 and a cylindrical hub portion 84,adapted to fit snugly in slot 14 and lateral opening 8|, respectively.In similar fashion, lower fixed bearing block 59 is provided at its endwith a lateral opening 85 accommodating a draw nut 86. The latter drawnut, as also sho-wn in Fig. 19, is provided with a generally rectangularend or base portion 81 and a cylindrical hub portion 88 adapted to itsnugly in slot 16 .and lateral opening 85, respectively. An end plate 89is secured to the free ends of lower fixed bearing block 59 and upperfixed bearing block 62, as shown in Fig. 8, by a plurality of bolts.Cylindrical hub portion 84 of draw nut 82 is in turn provided with alateral square-threaded opening 90 into which fits a complementarysquare-threaded draw screw 9|, the other end of which terminates in ashaft extension 92 extending through the bearing 93 of adraw bar 94secured to upper lateral sliding bearing block 13 by means of pluralityof bolts. In similar fashion, hub portion 88 of draw nut 86 is providedwith a lateral sqaure-threaded opening 95 into which lits acomplementary squareheaded draw screw 96, the other end of whichterminates inl a shaft extension 91 eX- tending through the bearing 98of a draw bar 99 secured to lower lateral sliding bearing block 15 bymeans of a plurality of bolts.

As shown in Figs. 8 and 19, end plate 89 is provided at its end withslots |00 and |0| to accommodate draw screws 9| and 96, respectively. Asqueeze roll adjustment gear |05 is integrally secured to the free endof shaft extension 92, the hub portion of the gear being in contact withhub 93 of draw bar 94 to make a tight assembly. A complementary squeezeroll adjustment gear |06 is integrally secured to the free end of shaftextension 91, theV hub portion of the gear being in contact with hub 98of draw bar 99 to make a tight assembly. A squeeze roll adjustmentpinion |01 fits in meshed engagement with and between adjustment gears|05 and |06, the pinion being integrally secured to a shaft |03, theinner end of which ts in a sleeve bearing |09 fitted in and secured tothe midportion of end plate 89. A pair of spaced flanges ||0 and providea space in which gears |05 and |86 may turn in Ineshed engagement withthe teeth of pinion l01. The other end of shaft |88 is squared into agripping portion I2 adapted to fit into a socket crank I3 (see alsoFigs. 1 and 27).

Taking up endless conveyor 36, which is shown in Figs. 1, 3, 4, 5, 6,'1, 8, 20 and 21, particularly, it will be seen that a conveyor drivesprocket |5 is secured to power drive shaft 50. An endless drive chainH6 is mounted on sprocket H5, and a sprocket ||1 integrally mounted on apower take-oil shaft ||8 (see Figs. 1 and 7). The shaft is in turnmounted in a pair of spaced bearings H9 and E20 attached to a generallyhorizontal support l2! by a plurality of bolts (see Fig. '1). Theendless conveyor proper comprises a pair of spaced endless sprocketchains |25 and |26 mounted on a pair of sprockets |21 and |28respectively, integrally secured to shaft H8, and a pair of spacedsprockets |29 and |30 mounted on a shaft |3I, the ends of which aresupported in a pair of spaced bearings |32 and |33 secured to horizontalsupport |2| with a plurality of bolts (see Figs. 20 and 2l). A pluralityof links |35 extend completely around the endless conveyor, the linksbeing attached at their sides to sprocket chains |25 and |26. A sheetmetal guard |36 is riveted to each link to provide a cover over thespace between adjacent links (see Figs. 3, 4, 5 and 6). Each link is, inaddition, provided with a central opening |31 (see Fig. 5) extendingthrough a depending boss |38 under each link. A mandrel support |39 fitsin opening |31, the upper end of which is provided with an enlarged bossportion |49 having a vertical opening |4| and a lateral set screw |42.The lower part of the mandrel support is provided with a removable andadjustable collar |43 securable to the support by means of a set screw|44. The construction is so designed that the bottom of boss |40 restsagainst the top of link |35 while collar |43 bears upwardly against thebottom of boss 38 in order to assure a tight assembly. Opening |4| inboss |40 is designed to receive a depending extension arm |45 of amandrel |46 adapted to rit into the threaded hole of a blank nut |41, alaterally extending base |48 being provided between the mandrel properand the depending extension arm which is designed to bear against thetop of boss |40. This mandrel is also shown in Figs. 10 and 11. -Setscrew |42 may be turned to secure the depending extension arm securely.

As shown more particularly in Figs. 20 and 21, longitudinal support |2|is in effect divided into a front portion |50 and a back portion |5|which are joined by a constricted central portieri 52 reinforced by apair of spaced reinforcing mem bers |53 and |54. Front portion |50 has acutaway portion |55 to accommodate sprockets |29 and |30, and backportion has a cut-away portion |58 to accommodate sprockets |21 and |28.Front portion |50 is provided with a pair of slack-takeup devices |19and |1| adapted to move bearing blocks |32 and |33, respectively, inorder to take up slack in endless conveyor 38. A pair of spaced mandrelguides |12 and |13 extend lengthwise across the mid-section oflongitudinal support |2|. Guide |12 is fastened to brackets |14 and |15,while guide |13 is fastened to brackets |16 and |11. A pair of sprocketchain guards |18 and |19 similarly extend across longitudinal support|`2| and are secured to the same brackets.

As shown in Fig. 8, constricted central portion |52 of longitudinalsupport |2i, in other words the section of the support between frontportion |50 and back portion |5|, rests in a recess i8 in lower fixedbearing block 59, the recess .being somewhat wider than the constrictedcentral portion to permit lateral sliding movement of the A,

latter. An aligning plate |8| extends across the top of constrictedportion |52 as well as front and back portions |50 and |5| directlybelow mandrel guides |12 and |13. As more particularly shown in Fig. 8,each mandrel support |99 is adapted to move along the top of thealigning plate, thus accurately locating each nut |41 mounted on itsmandrel with respect to squeeze rolls 31 and 38. To assist in saddlinglongitudinal support |'2| on lower fixed bearing block 59, front portion|50 of the longitudinal support is provided with a pair ofvertically-spaced and laterally-extending pads |82 Iand |83 adapted tobear against the side of the bearing block. A similar pair of pads |86and |85 is provided on back portion |5| of the longitudinal supportadapted to bear against the other side of the bearing block. A pair ofspaced struts |88 and |81 extend from front part |59 to back part |5| oflongitudinal support 2| directly below bearing block 59, the strutsbeing provided with a pair of nuts at each threaded end to permit thedesired adjustments.

Referring more particularly to Figs. 3, 9, 1'1 and 18, the apparatusshown includes a nutaligner |90 which comprises a pair of spaced andparallel guide wires |9| and |92 extending in the direction of theendless conveyor, wire |92 extending forward farther than wire I9 Thewires are spaced a predetermined distance apart so that when nut |41mounted on mandrel |48 is passed toward the squeeze rolls and the sideof the nut strikes wire |92 and passes between both wires, the wiresfunction to align opposite sides of the nut in parallel relationshipwith the wires so that the opposite sides of the nut are presentedsimultaneously for engagement with the squeeze rolls. The ends of wire|9| are secured to a pair of upright supports |93 and |94, in turnsecured to brackets |95 and |98, which are fastened to the sides ofupper xed bearing .block 82. The ends of wire |92 are similarly securedto a pair of upright supports |91 and |98, in turn secured to a lateralbracket |90 which is fastened to the inner end of upper laterallyslidable bearing block 13.

A draw nut 205 with a generally rectangular end or base portion 206 anda cylindrical hub portion 201- is secured to front portion |50 oflongitudinal support |2| (see Figs. 3, '1, 9, 1'1, 20 and 21, andparticularly Fig. 1'1). In similar fashion, a draw nut 2|0 with agenerally rectangular end or base portion 2|| and a cylindrical hubportion 2|2 is secured to back .portion |5| of longitudinal .support|2|. Hub portions 201 and 2|2 are provided with square threaded Ylateralopenings into which t complementary square thread.. ed drawn screws 2 I3and 2|4, respectively. Draw screw 2|3 is mounted in a bearing 2|5integrally supported by a bracket 2 6 secured to lower fixed bearingblock 59, the draw screw being provided with a pair of collars 2|1 and2|8 secured thereto at either side of bearing 2|5. An endless conveyoradjusting gear 2 I9 is mounted at the other end of the draw screw. Insimilar fashion, draw screw 2|4 is mounted in a bearing 225 integrallysupported by a bracket 226 secured to lower fixed bearing block 59, thedraw screw being provided with a pair of collars 221 and 228 securedthereto at either side of bearing 225. An endless conveyor adjustinggear 229 is mounted at the other end of the draw screw.

Referring to Figs. 8, 9, 17 and 27, it will be seen that shaft extension92 of draw `screw 9| is keyed to and extends through hub 235 vofadjusting gear |05 a convenient distance, the shaft extension beingprovided with an elongated lateral opening 238 in which an indicatorshaft 231 is securely fitted. As socket crank ||3 is turned to moveupper laterally slidable bearing block 13 and lower laterally slidablebearing block 15, and hence endless conveyor 36, and their relatedparts, back and forth, indicator shaft 231 also turns. The outer end ofindicator shaft 231 extends through a xed bearing in casing or cover 35.An indicator pinion 238 is secured to the indicator shaft intermediatehub 235 and cover 35, the teeth of which mesh with the teeth of anindicator gear 239 mounted on a second indicator shaft 240 extendingthrough a bearing secured in cover 35, the outer end of shaft 2|0 beingprovided with an indicator hand 24|. In similar fashion, the outer endof rst indicator shaft 2,31 is provided Vwith an indicator hand 242.Referring next to Fig. 28, it will be seen that indicator hand 242 isassociated with an outer calibrated scale 243, advantageously subdividedinto thousandths of an inch. As shown, the scale is sub-divided intomain graduations of ten thousandths of an inch, totalling 250thousandths; in other words, 1A; inch. Indicator hand 24| is associatedwith `an inner calibrated counter scale 244 sub-divided as shown intomain graduations oi 25 units, totalling 150. Movement of largerindicator hand 242 in a clockwise direction from zero all Vthe wayaround the scale back to zero simultaneously moves smaller indicatorhand 24| in a counter-clockwise `direction one main graduation, namely25 units; that is, -1/4 inch. A movement of the smaller indicator handfrom 0 to 0, namely 150 units, corresponds to 1%. inches.

`The object vof the arrangement described is to indicate to the operatorthe amount of space existing between squeeze rolls 31 and 38 or theamount of adjustment to be made in the space between the rolls. The sizeof pinion |01, gears |05, |98, 2|9 and 229 and their teeth and the sizeof draw screws 9|, 95, 2|3 and 2|4 and their threads are so proportionedand correlated that when crank ||3 is turned, squeeze roll 31 moveslaterally twice as far as endless conveyor 36. This permits thecentering of each nut |41 midway in space 80 between squeeze rolls 31and 38.

As stated above in referring to Fig. 1, the apparatus includes aknurling device 39. The object of the knurling device is to provide thedeformed nuts, that is the lock nuts, with a suitable marking so thatthey may be distinguished readily from conventional nuts and to indicateYwhat 'portion of the nut is deformed. In the present construction, theknurling device cuts a criss-cross pattern of lines in the top of thelock nuts. The device is shown in more detail in Fig. 3, andparticularly Figs. 22 to 26, inclusive. Power take-01T shaft H8, whichoperates endless conveyor 36, is also used to operate the knurlingdevice. For this purpose, the far end of the shaft is provided with agear 256 which in turn meshes with a gear 25| mounted on a horizontaljack shaft 252 extending back over and across the endless conveyor. Thejack shaft is supported in a pair of spaced bearings 253 and 254, theformer bearing being bolted to a pair of spaced vertical columns 255 and256 and the latter bearing being bolted to a similar pair of spacedvertical columns 251 and 258, the bases of the co1- umns being bolted toback portion of horizontal support I2I. The other end of the jack shaftis fitted with a sprocket 259 on which is mounted an endless sprocketchain 266, also mounted on a sprocket 26| on a shaft 262 extendinglaterally back over the endless conveyor. Shaft 262 rests in two splitbearings 263 and 264, with a knurler roll 265 positioned therebetween,the bearings extending horizontally between a pair of vertical columns266 and 261 near one end and a similar pair of vertical columns 268and`269 near the other end, all of the columns being secured at theirbottoms to back portion |5| of horizontal support I2| and their upperends being threaded as shown.

The four upright columns are tted with three platens, a lower platen216, a middle platen 21| and an upper platen 212. The upper platen isprovided with a rising central rib section 213 at one end and a similarrising rib section 214 at the other end, these ribbed sectionsconnecting with a centrally disposed and a wider bearing portion 215.The threaded end of each vertical column 261, 268 and 269 ts in athreaded sleeve 216 extending through the platen, the sleeve in turnbeing keyed in each case to a sprocket 211, the construction beingidentical for the assembly at the upper end of the three verticalcolumns. The fourth vertical column 266 is provided with a modifiedsprocket 218, secured to a special sleeve 219, the upper end of whichterminates in an extension portion 286 adapted to t into a socket crank.An endless sprocket chain 28| is mounted on the four sprockets.

A vertical shaft 285 extends through bearing portion 215 of upper platen212, the lower end terminating in a head 286 to help hold it inposition, the upper portion of the shaft having keyed thereon a pinion281 meshing laterally with a pair of gears 288 and 289. The upper end ofshaft 285 terminates in an extension portion 296 adapted to fit a socketcrank. Gear 288 is integrally secured to the upper end of a thrust screw29| extending through a threaded hole in bearing portion 215, the lowerend of the thrust screw being adapted to engage a central rib 292 ofmiddle platen 21|. Gear 289 also carries a similar thrust screw 293 tobear upon the rib 292. An upper boss 291 and a lower boss 298 areprovided at each of the holes in lower platen 216 through which thevertical columns extend. to provide more bearing and guiding surface.Split bearings 263 and 266 are integrally secured to the bottomv oflower platen 216 by means of a plurality of stud bolts 299. The lowerplaten has a cut-away portion 306 through which the upper portion ofknurler roll 265 extends. Reinforcing plates 36| arc 56911996.51?Opposite sides to 'strengthen the.

10 platen in the areas adjacent cut-away portion 306.

A plurality of appropriately spaced bolts 365 extend through upperplaten 212, middle platen 21| and lower platen 216 and split bear-ings263 and 264 to help support the lower portions of the split bearings. Inaddition, each bolt is provided with a compression spring 366 betweenmiddle platen 21| and lower platen 216. As a result of the arrangementdescribed, shaft 262 and therefore knurling roll 265 are held in aposition to be moved upwardly or downwardly, as desired.

A rough approximation for the operative posi.-` tion of the knurlingroll is advantageously first obtained by tting a socket crank onextension portion 286 and turning it to move sprocket chain 28| aroundsprockets 211 and 218 and hence to move upper platen 212 up or down, asrequired. This is done to place thrust screws 29| and 293 in a favorableoperative position. When, therefore, a socket crank is fitted ontoextension portion 296 of vertical shaft 285, thrust screws 29| and 293are moved upwardly or downwardly, depending upon the direction ofrotation of the socket crank. If thrust screws 29| and 293 are forceddownwardly against central rib 292 of middle platen 21|, springs 866 areplaced under greater compression, thus forcing lower platen 215 andhence shaft 262 and knurler roll 265 downwardly. In other words, theknurler roll Ais forced more heavily against the top of deformed nut|41, and succeeding deformed nuts |41. If, however, the pressure of theknurler roll on the nut is too much, the operation may be reversed torelease the compressive force of springs 366.. Minute control of theamount of pressure of the knurling roll on the nut may thus be obtainedby the use of the socket crank on extension portion 296.

The apparatus shown includes special means for withdrawing the deformednuts from the mandrels as the endless conveyor moves around to itsdischarge end (see Figs. 1, 7 and 22). For this purpose, the apparatusincludes a pair of spaced supports 3|6 and 3| l, the upper ends of whichare attached to upright columns 251 and 255, and the lower ends to backportion |5| of horizontal support 12|. A pair of spaced deformed nutstrippers 3 2 and 3 l 3 are suitably suspended from supports 3|6 and 3|by a plurality of lateral arms 3|4. These strippers consist of strips ofthin curved sheet metal, the inner edge portions of which are adapted toengage the bottoms of the deformed nuts. As shown in Fig. 1, thecurvature of the strippers is such as to follow each mandrel to itsupper end as it moves around the discharge end of the endless conveyor;that is, around chain sprockets |21 and |28. Therefore, as the fore ortop parts of the strippers engage the bottom of each nut in its normalposition on the mandrel, and the mandrel continues in its course aroundthe sprockets, the deformed nuts ride onv the strippers and aregraduallyy moved upwardly to the top or end of the mandrels, from whichthe nuts are dropped. A chute SI5 is located at the discharge end of theendless conveyor, being secured to cover 35, as shown in Fig. 1l. tocatch the nuts and direct them into a bin 3|6 located under the chute.

In referring to Figs. 5, 10 and l1 above, brief reference is made tomandrel |46. lAs more clearly shown in Figs. 10 and 1l, the mandrelproper is divided into a lower cylindrical base portion 325 adapted tofit loosely in the lower prtion of blank nut |41, and an uppercylindric'al stop portion 326 of predetermined size adapted to act as astop (see Fig. 11) when squeeze rolls 37 and 38 force opposite sides ofthe upper portion of the nut toward one another and the upper threads ofthe nut are vbrought into engagement with the stop portion. A modifiedform of mandrel |46' is illustrated in Fig. 12, in which base portion325 and stop portion 326 are in the shape of a frustum of a cone. Inboth constructions, the surfaces are relatively smooth. The presentlypreferred construction is that of Figs. and 11 because the cylindricalbase and stop portions may be readily machined to size.

Lock nut `Ill'l is shown in hexagonal form with a threaded centralopening 33t. The opening at the bottom portion 332 of the blank iscircular but at the upper portion 333 it is generally elliptical, havinga minor axis 3311 and a major axis 335. The elliptical shape of theopening at the upper -portion of the blank is the result of compressingor squeezing 'the upper portions 333 and 331 of opposite sides of themain body of the blank toward one another at the top vportion to a depthof 1A; to 1/2 the nominal diameter of the mating screw beyond theelastic limit of the blank to provide a permanent distortion in theblank with the sides 338 and 339 of the opening on minor `axis -334pushed toward one another and with the 'sides 340 and 34! of major -axis335 pushed away from one another. The width of the top Yof the yopeningalong the minor axis is reduced by the distortion by an amount equal tothe t tolerance plus 0.001 tol 0.010 inch. The amount of inwarddistortion may be determined by measuring the distance from crest tocrest of the first or upper full thread in the opening. This may be donewith a Vernier caliper or a taper plug gauge.

`In a `presently pref-erred practice of the invention, the width of 4thetop of the opening along the `minor vaxis is reduced by the distortionby an amount to produce a friction locking torque of 11,5D2-4 to'8,20D2'5 on a lmating screw within the dimensional tolerances of itsclass of t, in which D equals the nominal diameter of the matingscrew-and the result obtained is pound inches of torque. This value maybe readily determined by screwing the lock nut .on a mating screw, suchas a bolt, with a conventional torque wrench.

Fig. V16 illustrates the use of the lock nut when screwed tightly onto abolt 342 to :secure the pieces of work`343 and 344. When the nut isapplied to the bolt, it Vmay be screwed at least A of the way freely`by-hand since thellowerpart di thenut is not distorted. ,'As the nutisscrewed further onto the bolt, the distorted upper portion of the nuttends to Vassume kits original undistorted form due to the resiliency ofthe metal wall of the -nutl The bolt threads force the compressedsides-of the--nut'apart against the spring action lof the distortedupperportionof the nut. As Yindicated -in the drawing, the threadsAalong the inwardly distorted -sides 338 and 339 on minor axis 334 ofthe -nut tightly `engage their mating threads on the bolt. vThis :springaction causes the -nut'to grip'opposite sidesof the bolt and by reasonYof the Iamountof theidistortion to make a strong friction pressureicontacton the top as wellas on the bottom of the bolt threads..Accordingly, theznut vrnot onlyvigrips the bolt .tightly but createsanadditional Vfiriction area on the threads by `pressing againstftheupper as well vas the -lower sides of `theboltfthreadseven when thenu'tis tightened against the work.

In 'order that lock nuts made according to the invention be of generalutility, it is highly ndesirable that they be adapted to receivestandard socket Wrenches and box end wrenches, as well as open endwrenches. In distorting the nut, its outside dimension Ameasured atright angles to the direction in which it is squeezed is increasedslightly. In other words, the distance across the nut is decreased alongminor axis 334 and increased along major axis 335. This increasedoutside dimension along the major axis maybe too great to permit placingka standard socket wrench or box end wrench of nominal size over thenut. t is therefore desirable to make the nut blanks in, for example,hexagonal form,-

somewhat smaller in cross-section than the conventional practice so thatwhen the distance across the top of the lock nut is vincreased along itsmajor axis, the nut ymay nevertheless t into the Wrench.

Some important advantages `of the lock nut of the invention are its easeof manufacture; its ease of application; it may be tightened withoutdamaging its own or its mating threads; it may be removed from a boltwithout excessive difiiculty; and it may be used again and again on thesame bolt or on a different bolt. In addition, the lock nut locks itselfto a bolt by a clamping ack tion strong enough to resist loosening undersevere vibration or repeated heavy shocks.

The application just described :may Ibe operated as follows:

Crank I i3 is turned clockwise or counter-clockwise, as required, toadjust the width of space 30 between squeeze rolls 37 and 38 toaccommodate the particular size of nut blank Ml to be deformed. In Fig.17, for example, the nut is relatively small while in Fig. 9 it isrelatively large. Operation .of crank H3 simultaneously adjusts theVspace between parallel'guide wires l-I and '192. Motor 47 is startedwhich in turn sets squeeze rolls 31 and 38, 4endless conveyor 36 andknurling device 39 in motion The driving parts are so proportioned andcorrelated that the endless conveyor, squeeze rolls and lknurler move atsubstantially lthe same .linear speed. A nut blank lill is mounted onthe free endof each mandrel |46 as .it approaches `-the parallel guidewires and thefsqueeze rolls. If a corner or corner portion of the nutstrikes guide wire 18'2, 'the nut is turned on the mandrel vto align apair of Aits opposite sides in parallel ,relationship with the guidewires. This relationship Vis maintained as the nut moves .forward .into.additional sliding contact'withguide wire 1.9!.. This .operationassuresproper presentation of the l.nut yto the squeeze rolls.

The squeeze rolls and the nut on themandrel are so positioned that onlythe upper portion of the nut cornes into squeezing engagement with therolls, the depth of squeeze, as pointed out above, being 1A; to 1/2 thenominal diameter of the mating screw. Since both squeeze .rolls Aarepower driven, the upper portion vof the nut is readily gripped bytherolls and deformed as it passes between them. VThe thrust rof the rollsis directly toward fone another so that little or no resultant forceextends 4downwardly toward laterally extending base 1'4'8 `of themandrel.

Crank H3 is suitably turnedto provide 'space im between the :squeezerolls 4with the .necessary width to deiorm the-upper portion of the nutLth'e requisite amount; upper portion 326 of the 'mandrel acting as astop against excessive deformation while at the 'same time assuring each:suc-

ceeding nut of an equivalent amount of deformation, falling within thelimits above mentioned. In practice, nuts as they come from the squeezerolls are measured to determine Whether the width of the top of theopening along the minor axis is reduced by the distortion by an amountequal to the t tolerance plus 0.001 to 0.010 inch. They are preferablytested with a torque wrench to determine whether the Width of the top ofthe opening along the minor axis is reduced by the distortion by anamount to produce a friction locking torque of 115D2-4 to 820D2-5 on amating screw within the dimension tolerance of its class of lit; inwhich, as previously pointed out, D equals the nominal diameter of themating screw and the result obtained is pound inches of torque. Anintermediate optimum value is selected and crank i I3 is turned this wayor that until the distorted nuts coming from the squeeze rolls matchthat value. Such checks and adjustments, if necessary, are made fromtime to time during the course of a days operation of the apparatus tomake certain that the lock nuts produced are substantially uniform intheir friction locking torque.

Although provision is made for knurling the top of each lock nut as itleaves the squeeze rolls, this is a convenience rather than a necessity.Furthermore, the nut blank could be knurled before it enters the squeezerolls, or for that matter, before it is mounted on its mandrel. Amongimportant advantages of the practice disclosed are the following: Theknurled top at once identifies the nut as a lock nut. Second, itindicates to the user that the knurling is adjacent the upper ordistorted portion of the nut and that the unknurled bottom should bepresented to a mating bolt to assure easy screwing of the nut at leastuntil the first threads of the bolt come into interfering or lockingengagement with the distorted threads of the lock nut. In addition, adistinctive knurling design may be employed to identify themanufacturers particular brand of lock nut.

In any event, as a given mandrel and nut are carried as a unit by theconveyor between the squeeze rolls, they pass under and in contact withknurling roll 265. As pointed out above in suiiicient detail, variousparts of the knurling device may be manipulated to vary the pressure ofthe roll on the top of the nut to assure the desired marking.

The conveyor then carries each succeeding knurled lock nut while stillmounted on its mandrel to strippers 3|2 and 3|3 where the nuts areforcibly removed, dropped rst into chute 3I5 and then into bin 3 l 6.

It will be clear to those skilled in this art that the specific methodand apparatus just described may be suitably varied While still fallingwithin the purview of the invention.

In my co-pending applications Serial Nos. 621,271 and 621,272, ledOctober 9, 1945, I have disclosed the same apparatus as disclosedherein. However, in my application Serial No. 621,271, I have claimed acombination of mechanism other than the knurling arrangement; While inmy application Serial No. 621,272, I have claimed a combination ofmechanisms including the knurling arrangement by which the presentmethod may be practiced expeditiously.

I claim:

1. In the manufacture of a lock nut from a nut having a threaded hole,the method which comprises inserting loosely in the hole an unyieldingresistance to inward movement of opposite sides of the hole in excess ofa predetermined amount, compressing opposite sides of the nut at itsupper portion until the threads at opposite sides of the hole engagesaid resistance, whereby the upper portion of the nut is distorted apredetermined amount, and, while said resistance is in the threadedhole, knurling the top of the nut.

2. The method as defined in claim 1, in which said knurling operation isperformed in a knurling zone, the method also comprising the step ofmoving said resistance to carry the nut through the knurling zone.

3. The method as defined in claim l, in which said compressing andknurling operations are performed in a compression zone and a knurlingzone, respectively, the method also comprising the step of moving saidresistance to carry the nut successively through said zones.

4. The method as defined in claim l, in which said knurling is performedby a rolling action.

5. The method as dened in claim 1, in which said knurling is performedby a rolling action in a knurling zone while moving said resistance tocarry the nut through the knurling zone. 6. The method as dened in claim1, in which said knurling is performed by a rolling action in a knurlingzone while moving said resistance to carry the nut through the knurlingzone, said rolling action being effected at a linear speed correspondingto the linear speed of the resistance while moving through the zone.

7. The method as denned in claim 1, in which said compressing andknurling operations are performed by rolling actions in a compressionzone and a knurling zone, respectively, the method also comprising thestep of moving said resistance to carry the nut successively throughsaid zones at a linear speed corresponding to the linear speed of saidrolling actions.

8. In the manufacture of a lock nut from a nut having a threaded hole,the method which comprises inserting loosely in the hole an unyieldingresistance to inward movement of opposite sides of the hole in excess ofa predetermined amount, knurling the top of the nut while the resistanceis in said hole to locate the nut, and compressing opposite sides of thenut at its upper portion until the threads at opposite sides of the holeengage said resistance, whereby the upper portion of the knurled nut isdistorted a predetermined amount.

9. In the manufacture of a lock nut from a nut having a threaded hole,the method which comprises compressing opposite sides of the nut at itsupper portion to force said sides toward each other, opposing saidcompression, after said upper portion has been distorted a predeterminedamount, by imposing from within the hole and against the threads anunyielding .resistance to further distortion, and, while said resistanceis still effective but after said compressing operation, knurling thetop of the resulting lock nut.

l0. The method as defined in claim 9, in which said opposite sides ofthe nut are compressed by squeezing said sides together.

ll. The method as defined in claim 9, in which said unyieldingresistance is imposed only against the threads in the upper portion ofthe hole.

JOHN W. NEFF.

No references cited.

